There is no need for the stats guys to have played baseball at all. You don't need to be a former MLB or even minor league player to analyze and understand the game. You do have to spend a LOT of time analyzing data, constructing hypotheses, testing them against more data, turning your hypotheses into actionable models, testing the models in the real world, hopefully beginning with your team's minor leagues and then continuing to further refine your models. It's not that other teams have baseball guys doing their analytical work. It's that other teams have been working at this a lot longer than our guys have. We aren't last, but we're among the new kids on the block.
When I worked in coal liquefaction technology, we hired a very bright chemist from MIT to pioneer use of gc-mass spec at our company. Since the coal liquefaction project was government supported, it became his first emphasis. He knew a lot about gc-mass spec, but had done zero prior work in identifying the chemicals present in coal liquid, which was the solvent for our reaction. He was supposed to develop a solvent-quality index which would help us improve our liquefaction practice. He never supplied any useful information -- not because he wasn't super bright, not because he wasn't hard working, not because he didn't have an intimate knowledge of how to do gc-mass spec, but because he was starting close to decade behind his counterparts at our competitors. He was as skilled at gc-mass spec as they were, he was identifying individual chemicals in the solvent and making steady progress. In a few more years, I'm sure he would have gotten there. Meanwhile, Richard Neville at Exxon had already developed a proprietary gc-mass spec based solvent quality index. We had a little over two years to catch up to what he already had. We didn't make it. We didn't not make it because Dick Neville started out knowing more about coal than our guy.
That is how I see the current status of use of stats analysis with the Phillies. It will eventually get there and close much of the gap between ourselves and Houston/Dodgers/etc. but it's not there now.